Article
- The EMBO Journal (2001) 20, 6735 - 6741
- doi:10.1093/emboj/20.23.6735
Involvement of the twin-arginine translocation system in protein secretion via the type II pathway
Romé Voulhoux1, Geneviève Ball1, Bérengère Ize2, Michael L. Vasil3, Andrée Lazdunski1, Long-Fei Wu2 and Alain Filloux1
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UPR9027, Marseille Cedex 20, France
- Laboratoire de Chimie Bactérienne, UPR9043, IBSM/CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
- Department of Microbiology, University of Colorado Health Sciences Center, Denver, CO, USA
Correspondence to:
Alain Filloux, E-mail: filloux@ibsm.cnrs-mrs.fr
Received 11 May 2001; Accepted 4 October 2001; Revised 17 September 2001
Abstract
The general secretory pathway (GSP) is a two-step process for the secretion of proteins by Gram-negative bacteria. The translocation across the outer membrane is carried out by the type II system, which involves machinery called the secreton. This step is considered to be an extension of the general export pathway, i.e. the export of proteins across the inner membrane by the Sec machinery. Here, we demonstrate that two substrates for the Pseudomonas aeruginosa secreton, both phospholipases, use the twin-arginine translocation (Tat) system, instead of the Sec system, for the first step of translocation across the inner membrane. These results challenge the previous vision of the GSP and suggest for the first time a mosaic model in which both the Sec and the Tat systems feed substrates into the secreton. Moreover, since P.aeruginosa phospholipases are secreted virulence factors, the Tat system appears to be a novel determinant of bacterial virulence.
Keywords:
- phospholipase,
- Pseudomonas aeruginosa,
- Sec machinery,
- Tat system,
- type II secretory pathway
